ARRANGEMENT AND METHOD FOR CONTROLLING A PLURALITY OF LIGHT-EMITTING DIODES WHICH ARE CONNECTED IN SERIES

摘要

An arrangement and a method for controlling a plurality of light emitting diodes which are connected in series to attain uniform distribution of a total current to several series connections, LED chains, connected in parallel to each other wherein circuitry-related expenditure and power losses occurring during the control process are minimized, include a first reference voltage generating unit and a second reference voltage generating unit, wherein a outlet of the first reference voltage generating unit is connected to a first and a second control circuit, and an outlet of the second reference voltage generating unit is connected to the second and the first control circuit, and an outlet of the first control circuit is connected to a control inlet of the first controllable semiconductor switch, and an outlet of the second control circuit is connected to a control inlet of the second controllable semiconductor switch.

主权项

1. Arrangement for controlling at least two LED chains connected in parallel, each LED chain composed of a plurality of light-emitting diodes connected in series, wherein a first end of each LED chain is connected to a first terminal of a constant current source, wherein a second end of each LED chain is at least indirectly connected with a second terminal of the constant current source via a current divider arrangement, the current divider arrangement comprising:
a first current controller comprising a first reference voltage generating unit connected in series with a first controllable semiconductor switch configured to control a current flowing through a first of the at least two LED chains, a first control circuit controlling the first controllable semiconductor switch and having a non-inverting input and an inverting input, with the inverting input receiving a first reference voltage depending on a current flowing through the first of the at least two LED chains, and a second current controller comprising a second reference voltage generating unit connected in series with a controllable semiconductor switch configured to control a current flowing through a second of the at least two LED chains, a second control circuit controlling the second controllable semiconductor switch and having a non-inverting input and an inverting input, with the inverting input receiving a second reference voltage depending on a current flowing through the second of the at least two LED chains, wherein the non-inverting input of the first controllable semiconductor switch receives the second reference voltage and the non-inverting input of the second controllable semiconductor switch receives the first reference voltage.